Quantitative organic vapor-particle sampler

ABSTRACT

The present invention concerns a quantitative organic vapor-particle sampler which can efficiently sample both semi-volatile organic gases and particulate components through the use of a unique sorbent resin coating and process.  
     The sampler of the present invention comprises in its broadest aspect a tubular device having an inlet at one end through which organic vapor/particles are introduced, an outlet at the other end through which gases exit, at least one annular denuder interposed there between which is coated on the inside surface of the annulus with a specially prepared resin absorbent, which selectively absorbs organic vapors contained in the gases introduced into the inlet, and a filter which traps and collects particles.  
     The invention further concerns a semi-volatile organic reversible gas sorbent for use in an integrated diffusion vapor-particle sampler comprising macroreticular resin agglomerates of randomly packed microspheres with the continuous porous structure of particles ranging in size between 0.05-10 μm.

[0001] This is a Continuation-In-Part Application of U.S. Ser. No.08/191,344 filed Feb. 2, 1994.

[0002] This invention was developed under National Heart, Lung, andBlood Institute of the Department of Health and Human Services, AREAL,and the U.S. Environmental Protection Agency grants. The U.S. Governmenthas certain rights in this invention.

BACKGROUND OF THE INVENTION

[0003] 1. Field of the Invention

[0004] The present invention concerns a quantitative organicvapor-particle sampler which can efficiently sample both semi-volatileorganic gases and particulate components through the use of a uniquesorbent resin coating and process.

[0005] The sampler of the present invention comprises in its broadestaspect a tubular device having an inlet at one end through which organicvapor/particles are introduced, an outlet at the other end through whichgases exit, at least one annular denuder interposed therebetween whichis coated on the inside surface of the annulus with a specially preparedresin absorbent, which selectively absorbs organic vapors contained inthe gases introduced into the inlet, and a filter which traps andcollects particles.

[0006] The invention further concerns a semi-volatile organic reversiblegas sorbent for use in an integrated diffusion vapor-particle samplercomprising macroreticular resin agglomerates of randomly packedmicrospheres with the continuous porous structure of particles rangingin size between 0.05-10 μm.

[0007] 2. Background and Related Disclosures

[0008] Assessment of both the vapor and particle components of varioussamples is important in a number of different situations. Accuratemeasurements of phase distributions of polycyclic aromatic hydrocarbons(PAH) in indoor air and environmental tobacco smoke (ETS) are needed inorder to assess exposure or danger of exposure to carcinogenic compoundssince lung deposition patterns of PAH depend on the distribution of thePAH between the gas and particle phases. Environmental fates ofsemi-volatile organic species are also phase-dependent becauseatmospheric reactions, and transport and deposition processes differ forgas and particulate semi-volatile species. Understanding thecontribution of organic species to visibility degradation requiresaccurate phase distribution data. Pollutant control strategies are alsophase-dependent.

[0009] Classic vapor-particle samplers, generally termedfilter-sorbents, allow flow of an air sample through a chamber. In thesesamplers, at the end of the chamber where the airstream enters thechamber is a physical filter that picks up the particulate matter fromthe sample, as well as any semi-volatile components associated with it.At the base of the chamber is a sorbent bed which then collects anyremaining gas phase materials. These gas-phase materials are thendesorbed and analyzed to determine the presence of the material in thesample.

[0010] Some specialized filter-sorbent samplers which can detectgas-phase organic polycyclic aromatic hydrocarbons (PAH) have beendeveloped. Cotham et al., developed such a sampler using polyurethanefoam for the sorbent (Environmental Science and Technology, Vol 26, pp469-478, (1992)). Kaupp et al used macroreticular polymeric resin beadsto test for PAH, which are described in (Atmosoheric Environment, Vol26A, pp 2259-2267, (1992).

[0011] Unfortunately, because these prior art sampler sorbent beds arepositioned downstream from the filter, desorption of semi-volatilecompounds from the filter creating negative artifacts, or collection ofgases by the filter creating positive artifacts, lead to incorrectmeasurements of gas-phase and particle-phase concentrations.Considerable experimental and theoretical efforts have been expended tounderstand and correct for these condensation and vaporization effects.

[0012] An important advance in vapor-particle samplers was described byPossanzini in Atmospheric Environment, 16:845-853, (1983). The samplerdescribed therein was able to test for inorganic acidic or basic gasesusing sorbents, such as sodium bicarbonate and citric acid.Additionally, Possanzini developed a different configuration for thesampler, allowing for greater efficiency while avoiding many of theproblems of the prior art samplers.

[0013] In contrast to the prior art samplers, in Possanzini'sconfiguration the sample is pulled through an annular space coated witha specific sorbent. The filter to collect the particulate portion of thesample is positioned downstream of the sorbent. This configurationobviates the positive and negative artifact problem of the prior artsamplers.

[0014] The Possanzini configuration allows this arrangement because ofthe design and function of his sampler. Possanzini's sampler includes anannulus through which the sample flows by positioning two tubesconcentrically to form such annulus. Other researchers have developedalternate means to produce the sample flow necessary for this samplingtechnique.

[0015] Broadly, Possanzini's improvement works as follows. when anairstream containing gases and particles is moving through tubes underconditions of laminar flow at a certain linear velocity, the particlesmove at the linear flow velocity. By contrast, the gases diffuserandomly in all directions at speeds determined only by their molecularweights and the temperature (kinetic energy).

[0016] When the airstream flows through an annulus, the dimension of theannulus (or annuli) is designed to be close to the diffusion path lengthof the gases. This results in the gases reaching the coated walls of thedenuder where they react in an acid-base reaction. The gases are thusremoved from the airstream, while the particle portion of the sampleproceeds at the linear flow velocity of the airstream, to be removed byfiltration. Any species desorbed from the filter are collecteddownstream of the filter.

[0017] The research community was very interested in sampling organicgases with the clearly superior efficiency using the Possanzini sampler.However, without a specific sorbent for organic components, this was notpossible. Prior to the present invention, gaseous organic componentscould not be desorbed to make them available for analysis, much less toallow quantitative analysis.

[0018] Krieger et al (Environ. Sci. Technol., Vol 26 pp 1551-1555, 1992)developed a diffusion denuder to fill the need for quantitative analysisof semi-volatile gases, but due to its small size, this denuder had nocapacity to test the particulate phase of a sample.

[0019] Krieger's diffusion denuder uses capillary gas chromatographicstationary phase columns that can be used for direct determination ofgas-phase semi-volatile organics. This denuder is very effective atquantifying volatile organic compounds but less effective at quantifyingsemi-volatile organic compounds. This denuder has a lower capacity forgas-phase organic compounds than the integrated organic vapor-particlesampler of the instant invention.

[0020] In order to gain some of the advantages of the Possanziniapproach for gaseous organic component analysis, some other differentialdiffusion samplers were developed where a sorbent was used only to cleanthe sample stream of volatile organic compounds, rather than serve inany testing capacity. In these systems, two separate sample chambers hadto be constructed in order to test two aliquots of each sample, one withand one without the non-reversible sorbent present. Typically each sidealso had a sorbent downstream of the filter. It was then hoped that thedifference in the collection on the filters and downstream denuders fromeach system would reflect the gaseous semi-volatile organic component ofthe sample. There was no quantitative finding available for anyparticular species in this “cleanse and test” system.

[0021] More recently, some other denuders were developed, such as, forexample denuder, to cleanse the sample stream of semi-volatile organicspecies described in Environ. Sci. Technol., Vol 22 pp 941-947, (1988).Coutant et al, developed silicon grease (Atm. Environment, Vol. 26A pp2831-2834, 1992) and Eatough et al, used filter paper impregnated withactivated carbon as a denuder coating to collect semi-volatile organiccompounds and pesticides (Atm. Environment, Vol. 27A pp 1213-1219,(1993)). Differential samplers represent an important advance overconventional samplers in the assessment of organic, gaseous species.However, as seen in U.S. Pat. No. 5,302,191, issued Apr. 12, 1994,sampling of atmospheric semi-volatile compounds remains a challenge, andis often inappropriately addressed by atmospheric chemists.

[0022] Recently, materials such as various resins have been utilized forcoating surfaces of vapor-particle samplers, described above.

[0023] Meitzner in U.S. Pat. No. 4,224,415, incorporated hereby byreference, discloses a method of making a macroreticular resin bycopolymerizing a mixture consisting of a monovinyl carbocyclic aromaticcompound or an ester of acrylic or methyacrylic acid, with apolyethylenically unsaturated monomer selected from the group consistingof a polyvinyl carbocyclic aromatic compound, an ester of a dihydricalcohol and an α-β-ethylenically unsaturated carboxylic acid, diallylmalcate, and divinyl ketone. The copolymerization was conducted whilethe monomers were dissolved in 25 to 150% by weight, based on monomerweight, of an organic liquid or mixture of organic liquids which acts asa solvent for said monomers but are unable to substantially swell thecopolymers resulting from copolymerization.

[0024] However, these resins were not successfully utilized forefficient sampling of semi-volatile organic gases and particulatecomponents and there still remain daunting limitations to the currentintegrated sampler technology in assessing volatile and semi-volatilegas species in a sample. While differential samplers address some ofthese needs, they require double equipment, and they require, as aprerequisite to obtaining correct results, that the sample be dividedperfectly. Because the species in question is never directly recovered,it is impossible to achieve accurate quantitative results for anyparticular gaseous organic component.

[0025] A sorbent which can be adhered to the inner surface of anintegrated sampler, and from which volatile and semi-volatile organiccomponents can be desorbed and assessed quantitatively, would representan important and dramatic advancement in atmospheric sampling.

SUMMARY OF INVENTION

[0026] It is one object of this invention to provide an improvedintegrated vapor-particle sampler, for the purpose of samplingsemi-volatile polycyclic aromatic hydrocarbons and other organicspecies, which is more efficient than the samplers of prior art.

[0027] It is another object of the invention to provide an integratedvapor-particle sampler which eliminates artifacts in the samplingprocedure.

[0028] It is another object of the invention to provide an integratedvapor-particle sampler which contains as a component thereof an improvedannular denuder.

[0029] It is another object of the invention to provide an integratedvapor-particle sampler containing an improved annular denuder whichallows both vapor and particulate phase organic species to be recoveredand quantified.

[0030] It is another object of the invention to provide an integratedorganic vapor-particle sampler whose parts can be used in severaldifferent configurations, depending on the purpose of its use.

[0031] It is another aspect of the invention to provide a semi-volatileorganic reversible gas sorbent for use in an integrated diffusionvapor-particle sampler comprising macroreticular resin agglomerates ofrandomly packed microspheres with the continuous porous structure ofparticles ranging in size between 0.05-10 μm.

[0032] It is still another object of the invention to provide a sorbentcoating which will not release particles when air flows over or throughthe coated air sampling device.

[0033] It is yet another object of the invention to provide a sorbentcoating which does not use adhesives which could dissolve in solventwashes of the coated surface.

[0034] It is still yet another object of the invention to provide aprocess for sampling semi-volatile organic compounds using the improvedintegrated vapor-particle sampler.

[0035] It is another object of the invention to provide a process forcoating a denuder which minimizes displacement of the absorbent duringtransport, collection, and subsequent extraction for analysis.

[0036] It is still another object of the invention to provide a processfor extraction of organic species from the coating of the annulardenuder.

BRIEF DESCRIPTION OF THE DRAWINGS

[0037]FIG. 1 is a side view of the integrated vapor-particle sampler ofthe invention with portions cut away, where three denuders are placed infront of the filter pack.

[0038]FIG. 2 is a side view of an alternate embodiment of the integratedvapor-particle sampler of the invention, with portions cut away, wheretwo denuders are placed in front of the filter pack and one denuder isplaced after the filter pack.

[0039]FIG. 3 is a cross-sectional view of a coated single-channelannular denuder.

[0040]FIG. 4 is a cross-sectional view of a multi-channel annulardenuder.

[0041]FIG. 5 is a plan view of a multi-channel annular denuder.

[0042]FIG. 6 is a photo-micrograph showing the surface of an sandblasteduncoated glass denuder.

[0043]FIG. 7 is a photo-micrograph showing the surface of a sandblastedresin coated denuder of the invention.

[0044]FIG. 8 shows semi-logarithmic plots of several gas-phase PAH as afunction of denuder position, for various flow rates and two samplingtimes.

[0045]FIG. 9 shows semi-logarithmic plots of outlet concentration toinlet concentration of several gas-phase PAH concentrations as afunction of length of denuder to volume of sampled air, for various flowrates and two sampling times.

DEFINITIONS

[0046] As used herein:

[0047] “Integrated organic vapor-particle sampler (IOVPS)” means anapparatus able to quantitatively sample and separate semi-volatileorganic gases and particulate components.

[0048] “Macroreticular” means the unique structure of the polymers usedin the present invention which are produced by a phase separationtechnique utilizing a precipitating agent.

[0049] “Microporosity” or “microreticularity” means molecular porositypresently known in the art as essentially homogenous crosslinked gelswherein the pore structure is defined by molecular-sized openingsbetween polymer chains.

[0050] “Macroreticular resins” means resins which contain significantnon-gel porosity in addition to the normal gel porosity, where thenon-gel pores have been seen, by electron micrographs, to be channelsbetween agglomerates of minute spherical gel particles, the prior artgel resin having a continuous polymeric phase while the macroreticularresin having agglomerates of randomly packed microspheres with acontinuous non-gel porous structure.

[0051] “Porous” as used herein refers to the channels or openingsbetween agglomerates of minute spherical particles.

DETAILED DESCRIPTION OF THE INVENTION

[0052] The present invention concerns a quantitative organicvapor-particle sampler which can efficiently sample both semi-volatileorganic gases and particulate components through the use of a uniquesorbent resin coating.

[0053] The invention further concerns a semi-volatile organic reversiblegas sorbent for use in an integrated diffusion vapor-particle samplercomprising macroreticular resin agglomerates of random packedmicrospheres with the continuous porous structure of particles rangingin size between 0.05-10 μm.

[0054] In addition to the resin coating, the invention concerns aprocess for sampling organic vapor/particle gas streams using thesampler of the invention.

[0055] I. Integrated Organic Vapor Particle Samplers

[0056] A. Description of the Integrated Organic-Vapor Particle Samplerof the Instant Invention

[0057] The present invention involves a quantitative integrated organicvapor-particle sampler (IOVPS) comprising a new resin-coated annulardenuder and filter, which enable organic vapor/particle compositions tobe efficiently phase separated and quantitatively measured using aunique sorbent resin coating.

[0058] The sampler of the present invention comprises in its broadestaspect a tubular device having an inlet at one end through which organicvapor and particles are introduced, an outlet at the other end throughwhich gases exit, at least one annular denuder interposed therebetweenwhich is coated on the inside surfaces of the annulus with a speciallyprepared resin absorbent which selectively absorbs organic vaporscontained in the gases introduced into the inlet, and a filter whichtraps and collects the particulate components.

[0059] The IOVPS of the present invention are designed to directlymeasure semi-volatile organic species in both the gas-phase andparticle-phase. Since lung deposition patterns of polycyclic aromatichydrocarbons (PAH) depend on the distribution of PAH between the gas andparticle phases, accurate measurements of phase distributions of PAH areneeded in order to assess exposure to carcinogenic compounds.

[0060] The IOVPS of the invention and its various individual componentsare seen in FIGS. 1-5. FIG. 1 shows one embodiment of the sampler of thepresent invention.

[0061] As shown in FIG. 1, the integrated organic vapor-particle sampler10 of this invention comprises an elongated tubular device verticallypositioned having attached a cyclone component 12 at the lower end and afilter pack component 14 at the opposite and upper end. An inlet pipecomponent 16 is joined to the cyclone 12 by means of a coupler 18. Anoutlet tube 20 projects upward from the filter pack 14.

[0062] Positioned intermediate between the cyclone 12 and the filterpack 14 is a plurality of annular denuders 22, 24 and 26 connected toeach other, and also to the cyclone 12 and to the filter pack 14 bymeans of connectors 28, 30, 32, and 34.

[0063] The cyclone 12 has an interior baffle arrangement 13 that allowslarge particles of particulate matter to fall to the floor while gaseouscomponents rise upward when the gas/particulate mixture enters thecyclone through the inlet pipe 16.

[0064] The filter pack component 14 comprises an annular support whichholds a glass fiber or other type of filter mounted there.

[0065] The individual annular denuders 22, 24 and 26 connect to theconnectors 28, 30, 32 and 34 by means of threads on the ends of thedenuders (not shown) engaging complementary threads on the connectors(not shown). Annuli of the denuders is coated with a resin.

[0066]FIG. 2 shows an alternate embodiment of the integrated organicvapor-particle sampler of FIG. 1.

[0067] The elongated tubular device 11 comprises two denuders 22 and 24,placed between the cyclone 12 and the filter pack 14 and one additionaldenuder 27, placed between the filter pack 14 and the outlet tube 20.

[0068] The annular denuders 22, 24 and 27 are connected to each other,to the cyclone 12, the filter pack 14, and the outlet tube 20, by meansof connectors 28, 30, 32 and 34 by means of threads on the ends thedenuders (not shown) engaging complementary threads on the connectors,cyclone 12, filter pack 14 and outlet tube 20 (not shown).

[0069] The annular denuder sections, shown as 22, 24, 26 and 27 in FIGS.1 and 2, are coated with ground sorbent particles. The ground sorbentparticles adsorb gases from the airstream. The filter pack is a holderfor one or more glass or quartz fabric filters which sieve the airborneparticles from the airstream. Couplers and fittings are used to connectthe components.

[0070]FIG. 3A is a cross-sectional view of a coated single-channelannular denuder. FIG. 3B represents a section of the denuder seen inFIG. 3A.

[0071] As shown in FIG. 3A, the annular denuder 22 comprises an outerhollow cylindrical tube 36 and an inner cylindrical rod 38, the two rodshaving the same central axis, and the outer hollow cylindrical tube 36being concentric with respect to the inner cylindrical tube 38.

[0072] The inner cylindrical rod 38 is inset 25 mm from one end of theouter cylindrical tube 36. This end is called the flow straightener end.The other end of the inner cylindrical tube 38 is flush with the otherend of the outer cylindrical tube 36. Both ends of the inner cylindricaltube 38 are sealed.

[0073] The inner surface 40 of the outer hollow cylindrical tube 36 andthe outer surface 42 of the inner cylindrical tube 38 define an annulustherebetween, of which surfaces are coated with a macroreticular resinof the invention described below, and through which annulus the organicvapor/particulate composition passes.

[0074] The tubes are connected to each other with small epoxy resinspacers placed at each end of the tubes. The epoxy resin spacersseparate the tubes, enabling the annulus to be defined therebetween.

[0075] The actual physical components of the denuder can be purchasedcommercially from University Research Glassware, 118 E. Main St.Carrboro, N.C. 27510. The improved sampler of this invention lies in theparticular resin applied to the inside surfaces of the denudercomponent.

[0076] B. Preferred and Alternate Embodiments

[0077] One alternate embodiment of the invention, for example, places adenuder or a sorben; bed after the filter pack to collect and measureblow-off from the particles caught on the filters. This embodiment ofthe integrated organic vapor-particle sampler is shown in FIG. 2.

[0078] In the most preferred embodiment of the invention the integratedorganic vapor-particle sampler (IOVPS), the denuder is formed of twoconcentric tubes 36 and 38 which define an annulus therebetween.

[0079] Yet another embodiment of the invention utilizes three or moreconcentric tubes with an annulus defined between each pair of adjacentconcentric tubes. A cross section of such a multi-channel denuderconsisting of four concentric glass tubes is shown in FIG. 4. FIG. 4 isthe cross-sectional view of a multi-channel denuder 43 consisting offour concentric glass tubes 44, 46, 48, 50. FIG. 5 shows (partially insection) the multi-channel denuder 43 of FIG. 4 in side view.

[0080] In still another embodiment of the invention the annulus of theannular denuder is lined with polyurethane foam.

[0081] Still another embodiment of the IOVPS combines the coating of theIOVPS with structural elements of Gas and Particle (GAP) samplers whichare similar in design to the IOVPS, but have thirty times the surfacearea. The Gas and Particle samplers were designed for operation asdifference denuders for measurement of the phase distributions ofpesticides in outdoor air.

[0082] The IOVPS of the invention has been developed to use hardwarethat has already been validated for sampling of acid gases. The samplergeometry and flow characteristics have been thoroughly investigated. Theadvantages of sampling gas phase pollutants with annular diffusiondenuders have now been extended to organic species that are adsorbed bythe macroreticular resin XAD-4 and similar adsorbents.

[0083] The modular design of the IOVPS allows the configuration of itscomponents to be tailored for the needs of each investigation. Forexample, the total length of the denuder section can be adjusted bychoice of the number of denuders used, and different coating types couldbe used in the different pre-filter sections. The filter holder cancontain up to four filters if desired. The post-denuder section can be adenuder, sorbent bed or polyurethane foam collector.

[0084] From the foregoing, one skilled in the art can recognize that thepresent invention provides a new instrument for the quantitation ofgas-phase and particle-phase species of semi-volatile organic compounds.The foregoing disclosures and descriptions of the invention areillustrative and explanatory of the invention. Without furtherelaboration, it is believed that one of ordinary skill in the art can,using the preceding description, utilize the present invention to itsfullest extent.

[0085] Additional embodiments will be obvious to those skilled in theart of the present invention. Various materials may be used which meetthe requirement of macroporosity discussed herein. A variety of denudergeometries may also be used which are functionally equivalent to thedenuder geometry illustrated herein. Alternative methods of preparingthe denuder with the advantageous coating described below may be used.

[0086] The IOVPS represents a significant improvement on conventionalfilter-sorbent bed samplers designed to sample gas-phase semi-volatileorganic compounds. It addresses the conventional samplers' inherentproblems, which include positive and negative artifacts and theinability to quantitatively recover gas-phase species. The IOVPS stripsthe gas-phase species from the air stream before particle collection bya filter. Although volatilization losses of semi-volatile species fromparticles are possible if the IOVPS is operated at a high face velocity,the IOVPS can be configured to correct for “blow-off” from the filters,by placing a denuder or sorbent bed downstream of the filter.

[0087] C. Assembly of the Integrated Organic Vapor-Particle Sampler(IOVPS)

[0088] The IOVPS has three primary elements: a size-selective inlet,annular denuder sections, and a filter pack for one or more filters.

[0089] These components are shown in FIGS. 1 and 2 described in detailabove.

[0090] The size-selective inlet, a Teflon-coated aluminum cyclone, whosefunction is to provide a 90°bend and orifice for separation of particlesgreater than 2.5 μm diameter from the sampled airstream was selected. Animpaction plate could also have been used, although the cyclone designis preferred for accurate separation of large particles from theairstream without contaminating the airstream with the grease which animpactor plate requires.

[0091] A selected plurality of annular denuder sections was coated withthe ground sorbent particles as described below. The coating adsorbsgases from the airstream. After coating, the denuder sections wereattached to the cyclone and each other by means of connectors.

[0092] A filter pack containing one or more glass or quartz fabricfilters which sieve the airborne particles from the airstream was thenconnected to the last denuder by means of a connector. optionally,another ground sorbent coated denuder section may be added after thefilter pack to collect any filter “blow-off” gases.

[0093] D. Samplers Used for Field Testing

[0094] The sampling configuration of IOVPS which was used for the fieldtesting is seen in FIG. 1. commercially available single channel glassdenuders, 22 cm long, from University Research Glassware, Carrboro, N.C.were used with a Teflon-lined aluminum cyclone preceding the firstdenuder. The cyclone was designed to remove particles with anaerodynamic diameter of less than 2.5 micrometers. Three denuders wereconnected in series between the cyclone and a Teflon filter pack.Pre-extracted and pre-weighed Teflon-coated glass fiber filters wereused. The sorbent bed sampler used an aluminum open-face filter holderwith Teflon-coated glass fiber filters followed by a glass tube packedwith 2.5 g cleaned XAD-4 resin. Flow rates were measured with a dry gastest meter. This configuration was used to evaluate breakthrough andcapacity as functions of flow rate and sampling time. The IOVPS sampledindoor laboratory room air in these experiments. As the emphasis was onevaluation of its collection of gas-phase components, no sorbent ordenuder was usually used downstream of the filter.

[0095] The configuration used to sample environmental tobacco smoke(ETS) is seen in FIG. 2. Two denuders were used between the cyclone andfilter pack, the third denuder followed the filter pack. Two filterswere used in the filter pack when sampling ETS. In one experiment thisconfiguration was also used to sample laboratory air. In thisconfiguration the whole phase distribution could be determined sincecorrection could be made for adsorption characteristics of the filterand for evaporation from particles.

[0096] II. Coating Resin and Its Preparation

[0097] One critical aspect of this invention is the inventivemacroreticular resin which is used to coat the annulus of the denuder ofthe integrated organic vapor-particle sampler of the instant invention.

[0098] A. Resin Materials

[0099] It has been found that gas phase polycyclic aromatic hydrocarbons(PAH) can be separated most efficiently from particulate matter andquantitative measurements made by using a macroreticular resin, such asdescribed in U.S. Pat. No. 4,224,415, incorporated by reference.

[0100] The macroreticular resin is the unique structure of the polymersused in the present invention which are produced by a phase separationtechnique utilizing a precipitating agent. While conventional prior artresins are essentially homogeneous crosslinked gels where the only porestructure is defined by molecular-sized openings, also calledmicroporosity or microreticularity, between polymer chains,macroreticular resins, by contract, contain significant non-gel porosityin addition to the normal gel porosity.

[0101] The non-gel pores have been seen by electron-micrographs to bechannels between agglomerates of minute spherical gel particles. Themacroreticular resin of the invention is seen in FIG. 7. FIG. 6 is aphoto-micrograph showing the surface of a sandblasted uncoated glassdenuder. FIG. 7 is a photo-micrograph showing the surface of thesandblasted denuder coated with macroreticular resin of the invention.

[0102] The prior art gel resin has a continuous polymeric phase whilethe macroreticular resin is clearly shown to be agglomerates of randomlypacked microspheres with the continuous non-gel porous structure. Theterm porous refers to the channels or openings between agglomerates ofminute spherical particles.

[0103] The absorbent of the present invention preferentially comprises amacroreticular resin which is applied to the inside surface of theannulus after preparation in the manner described hereinafter.

[0104] The most preferred macroreticular resin is a styrene divinylbenzene copolymer, commercially available from Rohm and HaasCorporation, Philadelphia, Pa., under the trade name XAD-4. XAD-4 is amacroreticular cross-linked aromatic polymer with a surface area of 780m²/g and a porosity volume percentage of 45%. Its pore size ranges from1-150 Å and its average pore diameter is 50 Å. XAD-4 density is 1.02g/mL.

[0105] Other suitable resins of the same family include those sold underthe trade names XAD-2, XAD-16, Chromosorb 102, and Ostion SP-1. These,and other macroreticular resins suitable for use in the annulardenuders, are set forth in Table 1. TABLE 1 Macroreticular ResinsSuitable for Use with the IOVPS Common Area Pore Size Name Type (m²g)(Å) XAD-1 styrene-divinylbenzene (DVB) 100 200 XAD-2styrene-divinylbenzene (DVB) 350 90 XAD-4 styrene-divinylbenzene (DVB)780 50 Ostion SP-1 styrene-divinylbenzene (DVB) 350 85 Chromosorb 102styrene-divinylbenzene (DVB) 350 90 Chromosorb 105 polyaromatic 650 500Chromosorb 106 polysterene 750 — Synachrom ethylvinylbenzene - DVB 57045 Porapak Q ethylvinylbenzene - DVB 735 — XAD-7 methylmethacrylate 45080 XAD-8 methylmethacrylate 140 250 Spheron MD methacrylate - DVB 320 —Spheron SE methacrylate-styrene 70 — Tenax - TA 2,6-diphenyl-p-phenyleneoxide 35 2000

[0106] Still other materials which can be used to coat the annulus ofthe denuders include non-bonded silica, bonded silica, alumina,fluoracil, activated carbons and carbon black, and a porous polymerresin available from many different sources, known under the trade nameTenax-TA. Tenax-TA, a 2,6-diphenyl-p-phenylene oxide resin, has asurface area of 35 m²/g, an average pore size of 200 nanometers, and adensity of 0.16 g/cc. Its properties are described in the AlltechChromatography catalog 300, page 157 (1993), incorporated herein byreference. Tenax-TA may be obtained from Alltech Associates, Inc., 2051Waukegan Road, Deerfield, Ill. 60015.

[0107] As stated above, the most preferred resin for coating of thesurface of the annulus is XAD-4. This is a styrene-divinyl benzene resinhaving an area of 780 m²/g and an average pore diameter of 50 Å.

[0108] Insofar as applicable for preparation of macroreticular resin ofthe invention, certain techniques described in and the U.S. Pat. No.5,302,191 itself are hereby incorporated by reference.

[0109] B. Preparation of the Coating

[0110] The coating material was ground into fine particles beforeapplication to the sampling equipment. About 8 grams of s macroreticularresin beads such as XAD-4, XAD-7, XAD-16, Tenax-GC, and various ionexchange beads, activated carbon particles such as Carbotrap andchromatographic-grade silica were ground separately using a commercialcentrifugal grinder. The grinder, a Fritsch Pulverisette, type 05.101,with an agate container and agate balls, operated at speed 7 of 10, forbetween 6 and 21 hours. The best grinding time depended on the nature ofthe particles. The aim was reduction of average particle size to lessthan 1 micrometer. XAD-4 which had been ground for six hours contained afew beads of unground resin which were removed from the batch beforefurther processing. It was also possible to obtain suitable particles byusing a hand-operated mortar and pestle to grind macroreticular resins.The finely-ground particles were separated from the remainder of thebatch by forcing the mortar output through a several layers of finestainless steel mesh.

[0111] C. Removal of Impurities and Very Fine Particles

[0112] The ground resin or other sorbent was extensively cleaned bysolvent extraction to remove impurities which, if not removed before airsampling, interfered with subsequent quantitative analysis of adsorbedspecies. After grinding, the particles were sonicated with 200 mLcyclohexane for 20 min. Aliquots (5 mL) of the suspension weretransferred to a vacuum filtration device loaded with an unlaminatedTeflon filter with nominal pore size of 0.5 micrometers and outerdiameter 47 mm (Millipore Corp., FHUP 0047). Vacuum was applied untilthe sorbent was almost dry, and then another aliquot of suspension wastransferred to the same device. The transfer and filtration wererepeated until half the slurry was transferred. Methanol was added intwo 25 mL aliquots. Vacuum was applied until the sorbent was dry enoughto crack. The filtration barrel was carefully removed, exposing theTeflon filter and cleaned sorbent which were then removed to a cleanwatch glass for air drying. The remainder of the cyclohexane slurry wastreated in the same way. Acceptable blank levels of the analytes ofinterest were found. Besides collecting the cleaned sorbent, thefiltration process removed sorbent particles smaller than the pore sizeof the filter which otherwise clogged capillary tubing in the analyticalinstrumentation whose use is described below. After the clean groundsorbent particles were dry they were carefully scraped off the filterinto a glass mortar and ground by hand for about one minute beforestorage in a stoppered glass bottle.

[0113] D. Properties of Resin Beads

[0114] The coating material is ground into fine particles beforeapplication to the sampling equipment. Macroreticular resin beads andvarious ion exchange beads, activated carbon particles such as Carbotrapand chromatographic-grade silica are ground separately using acommercial centrifugal grinder. The goal of the grinding is reduction ofthe average particle size to less than 1 μm. Remaining unground resin isremoved from the batch before further processing. It is also possible toobtain suitable particles by using a hand-operated mortar and pestle togrind macroreticular resins. The finely-ground particles are separatedfrom the remainder of the batch by forcing the mortar output throughseveral layers of fine stainless steel mesh.

[0115] Previously, when the diameters of a few unground XAD-4 particleswere measured using an optical microscope, typical diameter of theparticle was 0.76 mm. When a larger sample was measured by placing tenbeads end to end along a machinist's scale and noting the length, theaverage diameter was 0.95 mm.

[0116] The unground beads of the commercially available resins arealmost as large in diameter as the annular space of the IOVPS (1 mm) andwould cause complete blockage of the annulus because both surfaces needto be coated. For denuders of larger annulus (up to 3 mm in the highercapacity IOVPS), the annulus would be reduced to 1 mm and the presenceof such a bumpy coating would induce turbulence in the gas flow.Turbulence would lead to particle deposition and the phase distributionmeasurements would be impossible to achieve.

[0117] Additionally, unground beads do not form a slurry, but adheretemporarily to a glass surfaces rod as long as the beads are wet with acompatible solvent such as hexane. They fall off as the solventevaporates. The behavior is similar for attachment to sandblastedsurfaces. Such large particles cannot be used as a denuder coatingbecause their ability to adhere is exceeded by their mass. Properties ofground and unground XAD resin particles are seen in Table 2.

[0118] Table 2 below shows the surface area and volume calculations forunground and ground particles and the effect of grinding on surface areaof a slurry. TABLE 2 Surface Area and Volume Calculations for Ground andUnground XAD Resin Surface Area Volume Surface Ratio Diameter DiameterRadius cm² cm³ Area/Volume ground/ μm cm cm 4πr² ({fraction (4/3)})πr³cm⁻¹ unground unground 764 0.0764 0.0382 0.018337 0.000233 78.53 ground0.753 7.53E−05 3.77E−05 1.785−08 2.245−13 79681 1015 Surface SurfaceRatio Diameter Diameter Radius Area Volume Area/Volume ground/ μm m m m²m³ m⁻¹ unground unground 764 0.000764 0.000382 1.83E−06 2.33E−10 7853ground 0.753 7.53E−07 3.77E−07 1.78E−12 2.24E−19 7968127 1015

[0119] The ground resin or other sorbent must be cleaned by solventextraction to remove impurities which, if not removed before airsampling, interfere with subsequent quantitative analysis of adsorbedspecies. The particles are then sonicated and dried in a vacuumfiltration device loaded with a filter with nominal pore size of 0.5 μm.Methanol is added and vacuum reapplied until the sorbent is dry enoughto crack. The clean sorbent is then removed to a clean watch glass forair drying.

[0120] This filtration process removes sorbent particles smaller thanthe pore size of the filter which otherwise clogs capillary tubing inthe analytical instrumentation.

[0121] The clean dry ground sorbent particles are next carefully scrapedoff the filter into a glass mortar and ground by hand for about oneminute and then stored for future use.

[0122] E. Electron Microscopy

[0123] The coated and uncoated glass fragments were analyzed at the U.S.Environmental Protection Agency Scanning Electron Microscope Laboratoryin Research Triangle Park, North Carolina. The instrument was an AmrayModel 1000 scanning electron microscope, an analog instrument withmanual stage control and resolution of about 70 nm at 30 kev. Theinstrument was used at 20 kev, 50 μÅ beam, 26° tilt and 12 mm workingdistance. The samples were scanned at 500 and 2000 times magnification.Analysis of the particle size distribution of the XAD-4-coated fragmentfound that the coating was composed of particles with median and averagediameters of 0.7 and 0.9 μm, respectively. The geometric mean was 0.75μm, with a geometric standard deviation of 1.8 μm. The uncoated andcoated annular denuder surfaces, respectively, are seen in FIGS. 6 and7.

[0124] For testing, an annular denuder section (manufactured by URG) wastaken from the laboratory's stockpile at random and intentionallyshattered. Two small fragments were selected for electron microscopicanalysis. One 3 mm×3 mm fragment was coated by adding the fragment to 2mL of a slurry of ground XAD-4 (30 mg in 200 mL hexane) andultrasonicating for 5 minutes. The fragment was removed with tweezersand dried on a clean microscope slide in a nitrogen atmosphere for 5minutes. The process was repeated for a total of four times. After thelast coating, the surface had a visible thin coating of white powderwhich was not dislodged when the fragment was tapped gently. A similaruncoated fragment from the same denuder was also selected for electronmicroscopy.

[0125] III. Coating of Integrated Organic Vapor-particle Sampler

[0126] A. Techniques Used for Denuder Coating

[0127] Typically, a sandblasted glass annular denuder section is cappedat one end, filled with spectral grade acetonitrile, capped at the otherend, and cleaned by sonication. An ultrasonic bath large enough toaccommodate the whole length of the section is used. The cleaned sectionis dried by passing a low flow of clean nitrogen gas through it for afew minutes. The total mass of the clean uncapped denuder section isdetermined.

[0128] Slurries of the macroreticular resin are applied to the denuder.First, the slurry is sonicated briefly to assure suspension of the resinin hexane as some settling of the slurry may occur during storage. Thedenuder is then capped at one end and the slurry is poured into thedenuder. The other end of the denuder is capped and the denuder manuallyinverted about 10 times. The remaining slurry is drained from thedenuder into a beaker. The denuder is dried with a low flow of cleannitrogen for 30 to 60 seconds. The coated denuder is weighed again.

[0129] The coating, drying and weighing procedure of the denuder isrepeated at least ten times. After coating of the denuder is complete,hexane is poured into the capped denuder which is then inverted a fewtimes. The hexane is drained out.

[0130] The glued areas of the glass in the denuder ends are sonicated inhexane to remove any loose resin which might otherwise be blown off theglue surface during sampling.

[0131] The net coating mass is determined by weighing the coated denudersection after the hexane rinse.

[0132] The coating technique produces a stable even coating whichremains in place during sampling even at 20 L/min for 24 hours. However,the caps and connectors must be free of XAD-4 powder before they areattached to the coated denuders. Dry powder from the caps or connectorsmay lead to deposits of XAD-4 on the afterfilter. This would lead toerroneous results.

[0133] Sandblasted glass surfaces of any geometry can be coated byadapting the technique described above. For example, the suspendedslurry of sorbent in solvent can be poured over a flat surface; a tubecan be filled with the slurry, or the slurry can be poured through whilethe tube is rotated by hand or motor. A rod can be dipped into theslurry while it is suspended in a beaker or graduated cylinder.

[0134] The integrated organic vapor-particle samplers are inserted inthe chamber to be tested. The ventilation ducts and chamber doors aresealed shut with duct tape during the experiment to minimize the airexchange rate and improve the accuracy of the results of the analysis.

[0135] The integrated organic vapor-samplers are then removed insequence.

[0136] For studies performed in development of this invention,sandblasted glass annular denuder sections 22, 24 and 26, seen in FIG.1, were purchased from University Research Glass, Carrboro, N.C., partnumber URG 2000-30B, 220 mm length. They were capped at one end withTeflon-lined caps, filled with spectral grade acetonitrile, capped atthe other end, and cleaned by sonication for 20 minutes. An ultrasonicbath large enough to accommodate the whole length of a section was used.The cleaned sections were dried by passing a low flow of clean nitrogengas through them for a few minutes. The total mass of the clean uncappeddenuder was determined using a Mettler balance, Model H35AR (to 0.0001g). Slurries of density 50, 100, 200 and 250 mg ground XAD-4 in 30 mLhexane were prepared and used to test the coating procedure.

[0137] Each slurry was applied in the same way. First, the slurry wassonicated briefly to assure suspension of the resin in hexane. Somesettling of the XAD-4 was observed for a slurry density of 250 mg/30 mLhexane. Then the slurry was poured into the denuder which had beencapped at one end. Then the other end was capped and the denudermanually inverted about 10 times. The remaining slurry was drained intoa beaker from the denuder.

[0138] The denuder was dried with a low flow of clean nitrogen for 30 to60 sec. The coated denuder was weighed again. The coating, drying andweighing procedure was repeated at least ten times. After coating wascomplete, hexane was poured into the capped denuder which was theninverted a few times. The hexane was drained out, and each end wassonicated in hexane just covering the glued areas of the glass. Thehexane rinse removed any loose XAD-4 which might otherwise be blown offthe glass surface during sampling. The net coating mass was determinedby weighing the coated section after the hexane rinse.

[0139] The results showed that the greater the slurry density, the morequickly the denuder gained mass, but the maximum coating remained thesame regardless of the slurry density. Use of slurries of greater than500 mg/30 mL hexane led to streaky coating. However, the net coatingmass was typically 10-20 mg. for clean single-annulus denuder sectionsof 22 cm length which had previously been stripped of the XAD-4 bysonication in acetonitrile. Ethyl acetate removed XAD-4 even morethoroughly than acetonitrile. The net coating mass was reproducible to+1 mg for individual denuders. Based on the results described, a slurrydensity of 200 mg/30 mL hexane was chosen for routine coatingprocedures.

[0140] B. Preparation of Multi-channel Annular Denuders

[0141] The IOVPS may have one, but has preferably multiplicity ofdenuders.

[0142] The coating technique was applied to 5-channel annular denudersections (URG-2000-30x; sandblasted length 125 and 220 mm) whoseinterior surfaces had been sandblasted in the same manner as the singlechannel denuder sections. When ground XAD-4 was used as the sorbent, thenet coating mass was about three times that found for a single-channeldenuder of the same coated length. That result is consistent with themeasured difference in surface area between the single and five-channelannular denuder sections of similar sandblasted lengths.

[0143] C. High Capacity IOVPS

[0144] Gas and Particle (GAP) samplers are similar in design to theIOVPS, but the GAP samplers have thirty times the surface area. Theywere designed for operation as difference denuders for measurement ofthe phase distributions of pesticides in outdoor air.

[0145] An embodiment of the IOVPS which combines the coating of theIOVPS with structural elements of GAP samplers was prepared as follows.The adsorbent coating, crushed Tenax particles imbedded in silicone gum,was removed from the glass denuder sections of two GAP samplers byrinsing the inside of the denuder section with dichloromethane. The sixconcentric tubes were disassembled, and sections 55 cm in length weresandblasted on the inside and outside with silicon carbide particles ofmesh size 320.

[0146] The denuders were next cleaned in acetonitrile and hexane andthen coated with ground XAD-4 using procedures based on those describedabove. The tubes were carefully reinstalled into the outer shell of theGAP denuder. A slurry of 3.2 g ground XAD-4 in 490 mL hexane wassonicated for 10 minutes and poured into the reassembled denuder sectionafter one end had been capped. After capping the other end, the denuderwas rotated along its axis and from end to end for ten times in eachdirection. The slurry was poured out, collected, sonicated again for 5min, and then the coating step was repeated twice. Following a hexanerinse to remove fine particles, the coated GAP denuder section was driedwith a stream of dry nitrogen gas. The caps were reapplied, and thedenuder was stored at room temperature until the field test.

[0147] D. Coating Versus Sand Grit Size on Coated Glass Disks

[0148] Six pre-weighed Pyrex glass discs of 3.9 cm diameter were groundon one side with a range of Carborundum (silicon carbide) particles withgrit sizes 80, 150, 240, 320, 400 and 600. After cleaning by sonicationwith acetonitrile each disc was coated with XAD-4 using a modificationof the procedures disclosed in the application. Because the discs wereflat, the suspension was poured over three of them as they lay flat,ground side up, in a watch glass before the slurry was sloshed aroundover the discs ten times for good contact. Each disc was rinsed tentimes with hexane to remove unattached particles. Any powder on thesmooth back of the disk or edge was removed by wiping before massdetermination. The net coating mass and coverage data are presented inTable 3. TABLE 3 Coating v. Sand Grit Size for Coatings on SelectedGlass Discs Net mass Coverage Track width Grit size mg mg/cm² micrometer80 0.3 0.02 150 0.3 0.02 240 0.1 0.01 70 320 0.4 0.03 50 400 0.2 0.01 40600 0.3 0.02 20

[0149] D. Evaluation of Coating Stability on the Denuders

[0150] The coating stability was evaluated from the post-denuder filterin three ways: a) by visual examination, b) by mass determination, andc) by evaluation of the PAH concentration distribution for the particleextract.

[0151] After introduction of the final hexane rinse to the coatingprocedure there was routinely no detectable deposition of XAD-4 on thepost-denuder. Filter- and filter loading and extract PAH distributionwere similar for filters from both the sorbent and denuder samplingtrains. The coating was stable during sampling at flow rates up to 20L/min, as assessed by visual inspection of black after filters that wereused for 24 hours of pump operation. Inspection of Teflon filters thathad been used to filter denuder extracts showed that the coating was notremoved by static solvent extraction, using two rinses of theintra-annular space, at 45° C. When observed, deposition of ground XADon the post-denuder filter during sampling appeared as higher thanexpected filter mass and higher than expected semi-volatile PAHconcentrations in the filter extracts.

[0152] IV. Process of Sampling Semi-Volatile Organic Compounds

[0153] Apparatus assembly, resin preparation and purification, denudercoatings and sample preparations are as described above or below.

[0154] A. Laboratory IOVPS Emulation

[0155] The IOVPS was evaluated by sampling indoor laboratory air at roomtemperature (about 21° C.). The room was free of indoor combustionsources, and therefore the air represented outdoor air that had beenbrought into the building by the ventilation system. Sampling was doneat 5, 10 and 20 L/min for 3 and 6 hours, using three single-channelannular denuders in the configuration 0.075 seconds, respectively.Filter face velocities were 8, 17 and 33 cm/sec, respectively. Oneexperiment was done at 20 L/min for 22 hours. Separate clean componentswere used for each condition. The exposed denuders were refrigeratedbefore analysis if the extraction could not be carried out immediately.The filters were stored in the freezer before analysis.

[0156] Parallel sampling was done using a filter followed by a sorbentbed filled with 2.5 g unground XAD-4 resin beads. The filter-sorbentsampler was similar to that described by Loiselle et at., Indoor Air,2:191-210 (1991), except that the filter holder was stainless steel, andthe flow rate was 20 L/min. The XAD-4 resin had been cleaned bysequential Soxhlet extraction in dichloromethane and methanol. Afterheating in N₂ at 40° C. in a fluidized bed for four hours the resin wasstored in a sealed bottle until use.

[0157] B. Sampling Conditions

[0158] The optimal sampling conditions for indoor air withoutenvironmental tobacco smoke were chosen by consideration of the dataobtained at various flow rates and sampling times. This was done by a)determining the observed concentrations of all detected PAH in eachdenuder section; b) determining the percentages of naphthalene and itsmethyl derivatives, fluorene and phenanthrene that were trapped on thefirst of three denuders; and c) selecting conditions for which the firstdenuder collected at least 90% of the most volatile species, namely thethree naphthalenes. Compounds that are less volatile than thenaphthalenes were trapped at greater than 90% efficiency under thoseconditions.

[0159] C. Sample Extraction

[0160] The IOVPS is disassembled into its components. The open ends ofeach denuder are sealed with Teflon-lined screw caps and the denudersare then stored in a refrigerator until analysis. The filters areremoved from the filter pack, and stored in plastic petri dishes orother suitable sealed containers in a freezer (−20° C.) until analysis.

[0161] At the time of extraction the denuders and filters are warmed toroom temperature before extraction of the analytes. The annulus of eachdenuder is filled with an appropriate solvent and recapped after theaddition of an appropriate internal standard for recovery.

[0162] The denuders are sonicated or subject to static, microwave orSoxhlet extraction for the time necessary to dissolve the analytes inthe extraction solvent. Supercritical fluid extraction may also be used.The extract is separated from any loose sorbent particles by filtration.The extract is reduced in volume and the analytes determined by theappropriate analytical method.

[0163] The filters are extracted by contact with the appropriate solventusing sonication, microwave, Soxhlet or supercritical fluid extraction.

[0164] D. Analysis of Extracts

[0165] For analysis of polycyclic aromatic hydrocarbons, the extractionsolvent was cyclohexane. The extracts were passed through Teflon filters(unlaminated, Millipore Corp.) and then silica solid-phase extractioncolumns (packed in glass). Before analysis the solvent was exchanged toacetonitrile by evaporating the cleaned cyclohexane extracts on silicacolumns (200 mg) at room temperature and eluting with acetonitrile.Final sample volume was between 250 and 1000 μl. The injection volumefor high pressure liquid chromatographic (HPLC) analysis was 5 μL. Twounexposed coated denuders and pre-extracted filters were analyzed asblanks for every field test.

[0166] The extracts are passed through Teflon filters and the silicasolid-phase extraction columns packed in glass. Before analysis, thesolvent is exchanged to acetonitrile by evaporating the cleanedcyclohexane extracts on silica columns (200 mg) at room temperature andeluting with acetonitrile.

[0167] Extracts of the denuders are analyzed for PAH by adapting thedual-fluorescence technique developed by Mahanama et al. for analysis ofsemi-volatile PAH from naphthalene to chrysene Intern. J. Environ. Anal.Chem., 56:289 (1994).

[0168] A Hewlett-Packard high performance liquid chromatograph Model1090 M was used with a Vydac 201TP5215 column. The gradient programincreased the eluant strength from 38% acetonitrile, 2% THF in water, to95% acetonitrile, 5% THF, over 24 min at 0.5 mL/min. From 25 to 33minutes the flow increased linearly to 1 mL/min. After 4.5 min the flowrate returned to 0.5 mL/min, and the mobile phase composition returnedto the initial condition during the next two minutes. A 12-minuteequilibration at 0.5 mL/min followed. The column was maintained at 30.8°C.

[0169] Each fluorescence detector is independently programmed to changeexcitation and emission wavelengths to selectively detect the PAH ofinterest as they elute from the column. One detector started atexcitation and emission wavelengths of 220 and 348 nm, respectively, todetect naphthalene and its 1- and 2-methyl derivatives, acenaphthene andacenaphthylene. At 11.5 minutes it is switched to 263 and 371 nm todetect chrysene. The second detector started at 246 and 296 nm to detectbiphenyl and fluorene; at 11.95 minutes it switched to 245 and 359 nm todetect phenanthrene; at 16 minutes it switched to 245 and 391 nm todetect pyrene; and at 21.7 minutes it changed to 288 and 405 nm todetect benz(a)anthracene. These fluorescence programs were developed bystudying the excitation and emission spectra of standard compounds toselect conditions of both high sensitivity and selectivity. However,during the field testing with environmental tobacco smoke severalmodifications were made, as described above, to overcome real-worldinterferences from other PAH and their alkyl derivatives. The detectionand quantitation limits for both the gas and particle phases, derivedfrom analysis of blanks, are shown in Table 4. Recovery of both internalstandards from denuder extracts averaged 70%. PAH concentration datawere corrected for the observed recovery. Extracts of filters wereanalyzed for PAH using the dual-fluorescence detector technique ofMahanama, ibid (1994). TABLE 4 Detection and Quantitation Limits forSemi-Volatile PAH LLD(a) LLQ(b) LD(a, c) LLQ(b, c) PAH ng ng ng/m³ ng/m³Gas phase Naphthalene 13 44 43 130 1 - Methylnaphthalene 4.8 16 16 482 - Methylnaphthalene 19 62 63 190 Biphenyl 31 105 105 315 Acenaphthene& acenaphthylene 1.6 5.5 5.3 16 Fluorene 2.9 9.7 9.7 29 Phenanthrene 6.421 21 64 Anthracene 0.06 0.19 0.2 0.6 Fluoranthene 0.5 1.7 1.7 5.0Pyrene 0.5 1.7 1.7 5.0 Benz(a)anthracene 0.03 0.1 0.1 0.3 Chrysene 0.220.7 0.7 2.2 Particulate phase Naphthalene 5.2 18 17 521-Methylnaphthalene 3.5 12 12 35 2-Methylnaphthalene 3.1 10 10 31Biphenyl 0.74 2.2 2.5 7.4 Acenaphthene & acenaphthylene 0.42 1.4 1.4 4.2Fluorene 0.37 1.2 1.2 3.7 Phenanthrene 1.6 5.2 5.2 16 Anthracene 0.040.1 0.1 0.4 Fluoranthene 1.3 4.5 4.5 13 Pyrene 0.42 1.4 1.4 4.2Benz(a)anthracene 0.015 0.05 0.1 0.2 Chrysene 0.32 1.1 1.1 3.2

[0170] E. Comparison to Filter-Sorbent Bed Sampling

[0171] Conventional samplers were constructed with a 47-mm diameterfilter followed by a sorbent trap that contained between 0.15 and 2.5cleaned unground XAD-4 resin beads (20-60 mesh). In several experimentsthe filter-sorbent bed sampler was co-located indoors with the IOVPS andoperated for the same time and at the same flow rate. Because the twosampler types could yield different phase distributions of all but themost volatile PAH (due to the possibility of both positive and negativeartifacts expected from the conventional sampler), only species morevolatile than phenanthrene, i.e., the naphthalenes, acenaphthene,acenaphthylene and fluorene would be expected to be trapped with thesame efficiency by both sampler types. Gas phase concentrations of thesePAH were determined from the co-located samplers.

[0172] Data from sampling indoor laboratory room air at 20 L/min for 3hours are presented in Table 5. TABLE 5 Comparison of IOVPS to SorbentBed for Collection of Gas Phase PAH (a) LLD for Denuder Sorbent Den/SorbDen(b) PAH ng/m³ ng/m³ ratio ng/m³ Napthalene 545 798 0.68 2.9l-Methylnaphthalene 161 202 0.80 0.7 2-Methylnaphthalene 220 315 0.701.5 Biphenyl 61.6 102 0.60 3.2 Acenaphthene and 18.3 25.4 0.72 0.1Acenaphthylene Fluorene 17.0 19.9 0.85 0.5 Phenanthrene 38.4 41.5 0.931.9 Anthracene 0.61 0.64 0.95 0.11 Fluoranthene 6.06 7.25 0.84 0.74Pyrene 2.33 2.98 0.78 0.68 Chrysene 2.01 3.34 0.60 0.92 Average (Naph -Fluorene) 0.73 Average (Phen - Chry) 0.82

[0173] The PAH concentrations observed in this experiment were thehighest indoor concentrations encountered in this study, and thecapacity of the IOVPS in the configuration shown in FIG. 1 was exceededfor the most volatile species. The IOVPS-derived PAH concentrationsaveraged 73±9% of the sorbent-derived concentrations for PAH morevolatile than phenanthrene, namely the naphthalenes, acenaphthylene,biphenyl and fluorene. The observed differences in concentrations of thenaphthalenes are consistent with a deficit of about 25% in collection ofthe naphthalenes by the IOVPS at 20 L/min that can be deduced from thedata of FIG. 8. Since the IOVPS was operated at a flow rate above itsoptimal setting, incomplete trapping and/or losses of the most volatilespecies were not unexpected and are consistent with the resultspresented in Table 3 and FIG. 8. Denuder-derived concentrations forphenanthrene and the less volatile PAH from the IOVPS averaged 82±14% ofthe sorbent-derived values for the same experiment. However,phenanthrene and less volatile species may show “blow-off” artifactsthat increase apparent sorbent bed concentration. Since the datapresented in FIG. 8 indicate that phenanthrene was collected in thethree denuders with greater than 90% efficiency even under the samplingconditions of this experiment, and since the denuders have higherefficiency for the less volatile PAH, the lower gas-phase concentrationsmeasured with the denuder for fluoranthene, pyrene, and chrysene areconsistent with “blow-off” artifact from the particle-loaded filter inthe filter-sorbent bed sampler.

[0174] The available data indicate the IOVPS traps and recoverssemi-volatile PAH quantitatively when its capacity is not exceeded. Thisconclusion is consistent with the results obtained by other workers whoare evaluating the IOVPS in chamber studies of PAH reactions in thepresence of combustion effluents. Fan et al, presentation at theInternational Symposium on Toxic and Related Air Pollutants, Durham,N.C. (1993) subsequently published in Atmospheric Environment, 29:1171(1995), found that the concentrations of the naphthalenes, sampled at 20L/min for 20 minutes, obtained with the IOVPS agreed with those seen ina filter-sorbent bed sampler that used polyurethane foam as the trappingagent for gas-phase PAH.

[0175] V. Efficiency and Capacity of the Samplers

[0176] A. Performance of the Integrated Organic Vapor-Particle Samplerof the Invention

[0177] The efficiency of a sorbent-based sampler according to theinvention depends on the concentrations of the sorbed species in theairstream. At low concentrations the volumetric capacity depends on thetotal volume of air sampled and is independent of the gas-phaseconcentrations of the sorbed species. The holding power or efficiency ofthe trap is limited by the amount of air necessary to elute or displaceadsorbed material from the surface, as occurs in gas-solidchromatography. At higher inlet gas-phase concentrations the adsorptionsites could be filled before the volumetric capacity is exceeded becausethe weight capacity of the sorbent has been reached. The gas-phase PAHconcentration data obtained from sampling indoor air under variousconditions have been used to estimate these limits for the IOVPS. Theaim of these studies was to find useful operating range rather thaninvestigating the sorption mechanism in detail.

[0178] For efficiency and capacity determinations, it was assumed thatthe volumetric capacity Vg for a particular PAH had been exceeded fortotal air volumes for which the first denuder collected less than 90% ofthat PAH. The concentrations of all PAH were determined separately ineach denuder section. The percentages of naphthalene and its methylderivatives, fluorene and phenanthrene found on the first of the threeserial denuders are shown in Table 6.

[0179] Table 6 presents the percentage recoveries on the first of threedenuders in series for naphthalene with its methyl derivatives, fluoreneand phenanthrene in series versus flow rate and sampling duration. TABLE6 Percent Recovery of PAH on the First of Three Denuders Sampling timeFlow rate, L/min hours 5 10 20 Naphthalene 3 99 93 44 6 93 88 42Fluorene 3 100 96 75 6 93 78 71 Phenanthrene 3 100 97 81 6 89 91 77

[0180] The total PAH concentration was assumed to be the sum of theamounts found on each denuder. This assumption may have underestimatednaphthalene concentrations for sampling at 20 L/min based on the datashown in FIG. 8, described below. Based on this data, eachsingle-channel denuder section of 22 mm length, as described above, maybe advantageously used upstream of the filter to sample up to 1.8 m³indoor air, equivalent to 10 L/min for 3 hours or 5 L/min for 6 hours.Therefore, quantitative collection of naphthalene and othersemi-volatile PAH from 3.6 m³ can be done with two denuders in series at10 L/min for 6 hours or at 20 L/min for 3 hours. Alternatively, a single5-channel denuder with 22 cm length could be used to sample up to atotal volume of 5.4 m³, but some particle loss may occur. Asingle-channel denuder of increased length could also be used toincrease trapping capacity. Results seen in FIG. 8 suggest that fourdenuder sections would trap at least 955 of fluorene, phenanthrene, andless volatile species at 20 L/min during 6 hours of sampling.

[0181]FIG. 8 shows semi-logarithmic plots of several gas-phase PAH as afunction of denuder position, for various flow rates and two samplingtimes. Specifically, FIG. 8 shows semi-logarithmic plots of PAHconcentration data for naphthalene, 1-methylnaphthalene, fluorene andphenanthrene versus denuder position in the sampling train.

[0182] Positions 1, 2 and 3 correspond to 22, 24 and 26 in FIG. 1. FIG.8 designators represent flow rates as follows: open squares: 20 L/min, 3hr; closed squares: 20 L/min, 6 hr; open diamonds: 10 L/min, 3 hr;closed diamonds: 10 L/min, 6 hr; open triangles: 5 L/min, 3 hr; andclosed triangles 5 L/min, 6 hr.

[0183] The solid line shows trapping of 90% of each PAH on the first(upstream) denuder wherein (a) is naphthalene; (b) is1-methylnaphthalene; (c) fluorene and (d) is phenanthrene.

[0184] Position 1 refers to the denuder closest to the cyclone. Data foreach experiment were normalized so that the amount of each PAH on thefirst denuder was 100 arbitrary units.

[0185] The data for 2-methyl naphthalene were between those fornaphthalene and 1-methylnaphthalene. The naphthalenes were not trappedas effectively at 20 L/min as at 10 and 5 L/min. At 10 L/min logarithmsof the concentrations of the naphthalenes on each section were linearwith denuder position indicating exponential decay of gas-streamconcentrations. No naphthalenes were detected on the third denudersection when the flow rate was 5 L/min. Fluorene and phenanthrene werecollected on the third denuder only at 20 L/min, at which flow ratetheir concentration dependence also appeared to be exponential. Fluoreneand phenanthrene were not detected on the second denuder for sampling at10 L/min for 3 hours or for either sampling duration at 5 L/min. Eachsection of the figure has a line drawn to indicate 90% recovery of eachspecies on the first denuder for assumed exponential decrease of gasstream concentration versus denuder position.

[0186] As seen in FIG. 8, the method has a good reproducibility and thefour denuder IOVPS was able to trap more than 95% of PAH.

[0187] Based on the results presented above it may be concluded that theoptimal flow rates for routine operation of the IOVPS, when it isassembled with single channel denuders of the diameter use here, are5-10 L/min. Optimal sampling time will depend on the concentration rangeexpected, the denuder coating mass and total length of the pre-filtersection. In these studies 3 hours were sufficient to trap PAH in indoorlaboratory room air at 5 and 10 L/min. Two pre-filter denuders should beused when capacity limits for a single denuder may be exceeded. Samplingat 20 L/min with three or four denuders in series can also be used whennaphthalene is not of interest. At this higher flow rate, a largersample of particles is collected, and lower limits of detection resultfor both particulate and gas phase PAH.

[0188] Volumetric capacity (Vg) is about 2 m³ per denuder section forthese compounds. The data indicate that Vg is somewhat higher forsampling at 10 L/min for 3 hours, compared to sampling, at 5 L/min for 6hours. Apparently greater displacement or elution of PAH occurred at thecombination of lower flow rate (longer residence time) and longer totalsampling time. This result suggests that volumetric capacity depends onface velocity.

[0189] Lower limits to the weight capacity of the ground XAD-4 forseveral PAH were estimated from the amounts of these compounds collectedon the first and sometimes second of three denuders in series underconditions where breakthrough was observed. The XAD-4 coating mass wasmeasured for each denuder section. For the purposes of the estimate,breakthrough was assumed to have occurred when the amount trapped on thenext downstream denuder was more than 10% of the total found on allthree denuder sections. Based on this operational definition,breakthrough of naphthalene onto the second denuder was seen at 20 L/minfor 3 hours of sampling and at 10 L/min for 6 hours of sampling.

[0190] Breakthrough of naphthalene from the second denuder to the thirddenuder section occurred when the IOVPS operated at 20 L/min for 6 and22 hours. Under those conditions naphthalene migrated axially along thedenuder sections during the extended sampling period, so the volumetriccapacity was exceeded. Breakthrough was not observed at 20 L/min forfour-ring PAH. For the other PAH, breakthrough occurred only whensampling at 20 L/min for 3 hours or longer. The observed breakthroughshows that migration along the denuder sections dominated the collectionefficiency for the most volatile species, even though their higherdiffusivities compared to the heavier PAH would predict more efficientcollection in a diffusion denuder.

[0191] The weight capacity of ground XAD-4 for naphthalene, fluorene andphenanthrene, sampled together with other PAH, in indoor air was foundto be (+standard deviation; n=the number of observations) 57±16(n=8), >4.3+1.3 (n=3), and >7.7±3.4 (n=5) ng/mg XAD-4, respectively. Thehigh standard deviations reflect the fact that some of the denuders weretoo long to fit within the weighing compartment of the analyticalbalance and had to be weighed on a pan balance to the nearest 10 mg.Therefore, the coating mass was known only to only one significantfigure in those cases. The value found here for naphthalene is about 3times higher than estimated from breakthrough experiments for an XAD-4resin sorbent sampler. A typical denuder section can trap about 800 ngnaphthalene, 50 ng fluorene and 100 ng phenanthrene.

[0192] B. Assessment of TOVPS Performance

[0193] The performance of the IOVPS is assessed by using the models forannular denuder efficiency developed by Possanzini et al., and describedin Atmospheric Environment, 16:845-853, (1983) and Coutant, et al.,Atmos. Environ., 23:2205 (1989). The Possanzini model applies to asurface coating that irreversibly reacts with—the gas-phase component ofinterest. Coutant considers denuder performance when the reaction oradsorption probability is less than one for each collision of thegas-phase component with the denuder coating. Both models predict that,for sufficient denuder length, the ratio of outlet to inletconcentration for a trapped component of the airstream follows anexponential dependence on the ratio of denuder length to the total airflow.

[0194] For a single denuder section of length L the outlet concentration(C_(out)) of the gas phase component has been reduced from the inletconcentration (C_(in)) of the gas phase component by the amount of thegas phase component trapped on the denuder surface, per unit volume ofair. The efficiency is 1−(C_(out)/C_(in)).

[0195] For an IOVPS with several denuders the efficiency of the firstsection E₁ can be approximated by assuming that C_(in) is the sum of theamounts of gas phase component per m³ found on each section C₁, C₂, . .. C_(n), where n is the number of denuder sections. The outletconcentration after the first section is the difference between C_(in)and C₁. Therefore, the efficiency of one section is $\begin{matrix}{E_{1} = {{1 - \frac{C_{out}}{C_{in}}} = \frac{C_{1}}{C_{in}}}} & (1)\end{matrix}$

[0196] and the efficiency of two sections (used together) is$\begin{matrix}{E_{2} = \frac{C_{1} + C_{2}}{C_{in}}} & (2)\end{matrix}$

[0197] Practical use of these models for efficiency measurements isillustrated in FIG. 9.

[0198]FIG. 9 shows semi-logarithmic plots of outlet concentrationC_(out) to inlet concentration C_(in) several gas-phase PAHconcentrations as a function of denuder length to the volume of sampledair, for various flow rates and two sampling times.

[0199] The solid line shows trapping of 90% of each PAH on the inletconcentration for each denuder represent: (a) naphthalene; (b)1-methylnaphthalene; (c) fluorene; and (d) phenanthrene.

[0200]FIG. 9 designators are as follows: downward triangles, 5 L/min, 3hr; upward triangles, 5 L/min, 6 hr; open squares: 10 L/min, 3 hr; opendiamonds: 10 L/min, 6 hr; open horizontal hexagons: 20 L/min, 3 hr; andopen vertical hexagons: 20 L/min, 6 hr. For naphthalene andmethylnaphthalene sampled at 20 L/min, C_(in) was taken from thefilter-sorbent bed sampler data.

[0201]FIG. 9 shows semi-logarithmic plots of C_(out)/C_(in) forcollection of several PAH versus the ratio of denuder length to thevolume or air that passed through the IOVPS. The solid and open symbolscorrespond to the length of one and two sections, respectively. For onesection, C_(out)/C_(in)=(C_(in)−C₁)/C_(in). The solid symbols show(C_(in)−C₁)/C_(in) versus L1/V, where L1 is the length of the firstsection and V is the total volume of air sampled. The open symbols givethe data for two sections: C_(in)−[(C₁+C₂)/C_(in)], versus (L1+L2)/V.Data are shown for naphthalene, 1-methylnaphthalene, fluorene andphenanthrene samples in indoor air at flow rates of 5, 10, and 20 Llminfor 3 and 6 hours. C_(in) for 20 L/min includes the difference betweenamounts found on the denuder and parallel sorbent bed samples, i.e., theamounts not trapped by the three denuder sections of the IOVPS. The linedrawn in each section of the figure corresponds to the predictedexponential decay for a theoretical efficiency of 90% for each sectionwhen the IOVPS operates at 10 L/min for 3 hours sampling (or 5 L/min for6 hours). The ordinate value of 0.1 corresponds to 90% efficiency.

[0202] Besides confirming the volumetric gas capacity of 2 m³ perdenuder section for 90% efficiency, the data suggest that C_(out)/C_(in)is an exponentially decaying function of the ratio of denuder length toair volume, consistent with the models of Possanzini and Coutant.Efficiency improved as the molecular weight increased from naphthaleneto fluorene while the vapor pressure decreased. For naphthalene, besidesdiffusion and adsorption, axial migration also influenced the collectionefficiency for sampling at 20 L/min.

[0203] C. Design Criteria for IOVPS

[0204] A spreadsheet template has been created for calculation of thetheoretical efficiency of an annular denuder with dimensions of GAPsample using the Possanzini equation, where:

[0205] CO=initial gas-phase concentration;

[0206] C=gas-phase concentration after passage through the denuder withannulus d₂−d₁;

[0207] d₁=inner diameter of the annulus in cm;

[0208] d₂=outer diameter of the annulus in cm²/sec;

[0209] D=the diffusion constant of the adsorbed species, in cm²/sec;

[0210] L=length of the coated section;

[0211] F=flow rate in cm³/sec;

[0212] The efficiency according to this calculation is defined as:

E=100(1−C/C _(O)) where

C/Co=0.82 exp (−22.53 delta_(a)); and

delta_(a)=pi D L (d₁+d₂)/[4F (d₁−d₂)].

[0213] An example spreadsheet for the hybrid IOVPS-GAP sampler appearsin Table 7, given below. Table 7 represents an efficiency calculationfor naphthalene, which has D=0.081 cm²/sec at room temperature. TABLE 7Naphthalene at Room Temperature Inside Inside Outside Outside FlowN_(Ra) Std C/C_(o) Sect. Flow Annulus Diam. Area Diam. Area Width AreaVolume Cross Annulus Deviat. Flow (cm) (cm²) (cm) (cm²) (cm) (cm²) (cm³)Annulus (L/min) % Total (cm³/s) (%) (a) 0.20 34.56 0.60 103.67 0.20 0.2515.08 0.35 5.86 2.10 61.33 1.19 1.669E−1 (b) 0.80 138.23 1.26 217.710.23 0.74 44.65 1.04 17.34 6.23 70.52 0.90 1.184E−09 (c) 1.50 259.181.90 328.30 0.20 1.07 64.09 1.49 24.89 8.94 61.33 1.19 1.669E−12 (d)2.20 380.13 2.64 456.16 0.22 1.67 100.36 2.34 38.98 14.00 67.46 0.991.784E−10 (e) 3.00 518.36 3.40 587.48 0.20 2.01 120.64 2.81 46.85 16.8361.33 1.19 1.669E−12 (f) 3.80 656.59 4.40 760.26 0.30 3.86 231.85 5.4090.05 32.35 91.99 0.53 5.216E−06 (g) 4.80 829.38 5.10 881.22 0.15 2.33139.96 3.26 54.36 19.53 45.99 2.12 1.347E− 21 2816.44 3334.80 11.94716.62 16.70 278.33 100.00

[0214] Spreadsheets of this type have been used for prediction of thecollection efficiency of denuders of various dimensions. The theoreticalefficiencies assume perfect retention of the species of interest such asoccurs for the chemical reaction of HONO at a denuder surface coatedwith sodium carbonate. The actual efficiency of a denuder that traps byadsorption will be reduced by a factor that must be determinedexperimentally.

[0215] VI. Laboratory and Field Testing

[0216] Assembly of the equipment used for field testing is described inSection I. Coating was prepared and impurities were removed according toSection II. Electron microscopy was tested using procedure of SectionII. E. Extraction of analytes and analysis was performed according toSection III.

[0217] Extracts of the denuders were analyzed for PAH by adapting thedual-fluorescence technique developed by Mahanama et al. for analysis ofsemi-volatile PAH from naphthalene to chrysene Intern. J. Environ. Anal.Chem., 63: (1994). A high performance liquid chromatograph HewlettPackard Model 1090 M was used with a Vydac 201TP5215 column. Thegradient program increased the eluant strength from 38% acetonitrile, 2%THF in water, to 95% acetonitrile, 5% THF, over 24 min at 0.5 mL/min.From 25 to 33 minutes the flow increased linearly to 1 mL/min. After 4.5min the flow rate returned to 0.5 mL/min, and the mobile phasecomposition returned to the initial condition during the next twominutes. A 12-minute equilibration at 0.5 mL/min followed. The columnwas maintained at 30.8° C.

[0218] A. PAH Concentrations in Indoor Air and Simulated ETS

[0219] Table 8 summarizes the gas phase concentration data obtained withthe IOVPS for indoor air with no combustion sources and simulated ETS.The ranges and average concentrations are listed. PAH concentrationswere typically at least three times higher in ETS than in the relativelyclean room air of the laboratory. The concentration ranges are similarto those reported by other workers for indoor air with ETS. TABLE 8Concentration Ranges for Gas Phase PAH in ng/m³ Indoor air Environ.Tobacco Smoke PAH Min. Max. Avg. Min. Max. Avg. Naphthalene 162 545 338784 1690 1099 1-Methylnaphthalene 43 161 89 334 748 4852-Methylnaphthalene 67 220 142 526 931 719 Biphenyl 4.1 62 25 45 423 189Acenaphthene & 3.3 18 8.3 2.7 134 70 acenaphthylene Fluorene 4.1 17 8.257 267 129 Phenanthrene 18 38 23 43 151 99 Anthracene 0.1 0.6 0.4 3.9 2213 Fluoranthene 3.5 9.8 6.5 3.7 13 10 Pyrene 2.2 4.6 3.0 14 64 44Benz(a)anthracene 0.1 0.1 0.4 0.2 1.1 0.4 Chrysene 0.8 2.0 1.4 0.9 105.8

[0220] B. Phase Distributions and “Blow-off” of PAH in Indoor LaboratoryRoom Air

[0221] Table 9 below presents phase distribution data for phenanthrene,pyrene and chrysene in indoor laboratory room air samples collected at20 L/min for 3 hours (filter face velocity=33 cm/sec) during which theIOVPS and a filter-sorbent bed sampler operated for 3 hours. TABLE 9Phase Distributions of PAH in Indoor Laboratory Room Air PAH IOVPSFilt-Sorb Phenanthrene 0.097 0.033 Pyrene 0.157 0.053 Chrysene 0.2470.052

[0222] The particulate fractions were much lower for this environmentthan for ETS, but the sampling conditions, face velocities and samplingtimes, as well as the chemical composition, were very different. Theparticulate fractions obtained with the filter-sorbent bed sampler weresmaller for all three PAH than obtained using the IOVPS. The discrepancydecreased as the PAH volatility decreased. Two other parallel samplingexperiments also yielded pre-sorbent-bed filter samples that had lowerPAH concentrations than the filter samples obtained with the IOVPS. Thedata are consistent with PAH volatilization from the particles(“blow-off”) during sampling with the filter-sorbent bed. Post-filterdenuders were not used with the IOVPS in these experiments, so blow-offfrom the IOVPS-collected particles could not be assessed. However, in aseparate experiment using the configuration shown in FIG. 2 at facevelocity of 17 cm/sec (10 L/min, 6 hours) detectable amounts ofphenanthrene, pyrene, benz(a)anthracene and chrysene were found an apost-filter denuder. Since these compounds were not detected on thesecond denuder, they must have desorbed from the particles duringsampling.

[0223] C. Simulated Field Test for Phase Distributions for PAH inEnvironmental Tobacco Smoke

[0224] Simulated environmental tobacco smoke was sampled at 16 and 20°C. in a sealed (0.03 air exchange per hour, measured by SF₆ injection)36 m³ environmental chamber. A smoking machine (Arthur D. Little, Inc.,)was used in the center of the room, about 4 feet above the floor. Threereference cigarettes, Kentucky reference type 1R4F were machine-smokedsequentially at one 35 mL puff per minute. The mainstream smoke wasventilated outside the chamber, while the side stream smoke was emittedinto the chamber. Two IOVPSs were placed about 2 feet apart, with theirinlets about two feet above the floor. The samplers operated for onehour at 5 L/min starting about 20 minutes after the last cigarette wasextinguished. A filter-sorbent bed sampler was located about 2 metersfrom the IOVPS and operated at 5 L/min during the same period.

[0225] In a separate experiment in the 36 m³ chamber just one IOVPSoperated under the same conditions. A different chamber (20m³) was alsoused to sample ETS with the IOVPS for method development. In thatchamber four commercial filter cigarettes were machine-smoked using thesame smoking cycle (one every 25 minutes) over a 2 hour period the IOVPSoperated at 5 L/min for one hour during that time.

[0226] Table 10 presents phase distribution data for simulatedenvironmental tobacco smoke sampled at 16° C. TABLE 10 PhaseDistributions of PAH in Environmental Tobacco Smoke gas particlesfraction in PAH ng/m³ ng/m³ particles Naphthalene 822 <17 <0.02 1 -Methylnaphthalene 334 <12 <0.04 2 - Methylnaphthalene 526 <10 <0.02Acenaphthene & 72.2 <1.4 <0.02 acenaphthylene Fluorene 56.5 <1.7 <0.02Phenanthrene 43.1 <5.2 <0.11 Anthracene 3.85 <0.1 <0.03 Fluoranthene3.73 2.3 0.38 Pyrene 13.8 3 0.18 Benz(a)anthracene 0.15 10.4 0.99Chrysene 0.86 30.1 0.97

[0227] Both gas and particle phase data are average values for theco-located samplers when the IOVPS operated in the 36 m³ chamber for onehour at 5 L/min with face velocity =8 cm/sec. None of the more volatilePAH from naphthalene to anthracene were detected on the ETS particles,but fluoranthene and pyrene were found in both phases. Very littlebenz(a)anthracene and chrysene were found in the gas phase for ETS.Generally, the particulate fraction increased as molecular weightincreased and vapor pressure decreased. No detectable amounts of PAHwere found on the second filters or the post-filter denuders. No“blow-off’ of particulate PAH onto the backup filter substrate ordownstream denuder was observed for this experiment. In a separateexperiment using the same IOVPS configuration but with the chamber at20° C., fluoranthene, pyrene and chrysene were detected on thepost-filter denuder, indicating that some blow-off occurred. The amountsfound on the post-filter denuder averaged 16% of the total particulatePAH concentrations.

[0228] F. Limits of Detection

[0229] Because of the development of a new cleanup technique and thesensitivity of a newly-developed dual fluorescence detector highperformance liquid chromatography method, good precision has beenobtained with the sampler, for determination of the phase distributionof PAH in indoor air and ETS, in as little as one hour of sampling.Detection limits for phenanthrene, anthracene, pyrene and chrysene were10, 0.1, 0.8 and 0.4 ng/m³ respectively, for gas phase concentrations.Particulate phase detection limits for the same compounds were 2.6, 0.5,0.7 and 0.5 ng/m³, respectively for single channel IOVPS at flow ratesof 10 L/min.

[0230] G. Reproducibility of PAH Concentration Measurements

[0231] Reproducibility of PAH concentration measurement was determinedand results are seen in Table 11.

[0232] Table 11 presents PAH concentrations obtained from two co-locatedIOVPS that simultaneously sampled simulated environmental tobacco smoke.For denuder extracts of the upstream denuder the coefficient ofvariation ranged from 5% for 1-methylnaphthalene to 31% for pyrene andaveraged 14%. The high value for pyrene could be due to its co-elutionwith one of the methyl derivatives of phenanthrene. The fluorescenceexcitation and emission wavelengths for pyrene were chosen from theedges of its response envelope so that the methylphenanthreneinterference was minimized. The poor quantum yield for pyrene under thatcondition probably contributed to its high variability. Thehigher-than-average coefficient of variation for biphenyl may be due toits co-elution with 2-methylnaphthalene which was always found at higherconcentrations that biphenyl. Most of the semi-volatile PAH were notdetected in the particle phase. However, the four that were detected hadaverage coefficient of variation of 16%. TABLE 11 Reproducibility of PAHConcentration Measurements in Simulated Environmental Tobacco Smoke Gasphase Particle phase Std Std Avg. Dev Coeff Avg. Dev Coeff PAH ng/m³ng/m³ of Var. ng/m³ ng/m³ of Var. Naphthalene 822 82 9.9 bd — —1-Methyl- 334 18 5.4 bd — — naphthalene 2-Methyl- 526 40 7.6 bd — —naphthalene Biphenyl 45 10 21.6 bd — — Acenaphthene 72 12 16.5 bd — —and acenaphthylene Fluorene 56.5 3.6 6.4 bd — — Phenanthrene 43.1 6.715.5 bd — — Anthracene 3.85 0.53 13.8 bd — — Fluoranthene 3.73 0.53 14.22.3 0.07 3.1 Pyrene 13.8 4.3 30.9 3.0 0.3 11.1 Benz(a)anth- 0.15 0.02818.8 10.4 3.7 35.1 racene Chrysene 0.86 0.067 7.8 30.1 3.5 11.7 Average:14.0 15.2 Std Dev: 7.4 13.8

[0233] E. Comparison of the IOVPS to a Filter-Sorbent Bed Sampler

[0234] Comparison of the IOVPS to a filter-sorbent bed sampler forcollection of gas-phase PAH in indoor air at two flow rates is shown inTable 12. TABLE 12 Comparison of the IOVPS to a Filter-Sorbent BedSampler^(a) Uncer- Denuder/Sorbent Denuder/Sorbent tainty ratio ratioPAH % 10 L/min 20 L/min Naphthalene 11.0 0.83 ± 0.09 0.68 ± 0.071-Methylnaphthalene 11.7 1.11 ± 0.13 0.80 ± 0.09 2-Methylnaphthalene11.7 1.03 ± 0.12 0.70 ± 0.08 Biphenyl 22.7 1.03 ± 0.23 0.60 ± 0.13Acenaphthene and 14.0 0.87 ± 0.12 0.72 ± 0.10 acenaphthylene Fluorene30.4 0.95 ± 0.29 0.85 ± 0.26 Phenanthrene 14.5 1.18 ± 0.17 0.94 ± 0.14Anthracene 12.7 0.94 ± 0.12 0.95 ± 0.12 Fluoranthene 12.7 1.00 ± 0.130.84 ± 0.11 Pyrene 29.6 1.05 ± 0.31 0.84 ± 0.25 Chrysene 20.4 bd^(b)0.65 ± 0.13 Average (All PAH)  1.00 ± 0.10^(c)  0.78 ± 0.12^(c)

[0235] Comparison data from sampling indoor laboratory room air on twodifferent days are presented in Table 12 for two flow rates, 10 and 20L/min. Three-hour sampling periods were used for each experiment. Thedata indicate that the IOVPS traps and recovers semi-volatile PAHquantitatively when its capacity is not exceeded. At 10 L/min thedenuders and sorbent trapped the same amounts of semi-volatile PAE. Theratio of detectable PAH measured with the denuders to PAH collected bythe sorbent bed was 1.00±0.10. Therefore, the IOVPS-derived gas-phasePAH concentrations agreed with the conventional sampler results at thisflow rate and sampling time. The data show no apparent samplingartifacts.

[0236] Indoor air sampling with the IOVPS for three hours at 20 L/minyielded gas-phase PAH concentrations (summed from three serial denudersections) that averaged 78±13% of those derived from the sorbent bed.The denuder-derived PAH concentrations averaged 73±9% of thesorbent-derived concentrations for PAH more volatile than phenanthrene(the naphthalenes, acenaphthene, acenaphthylene, biphenyl and fluorene).The capacity limits for these species had been exceeded under theconditions of this experiment, as shown in FIG. 9. Denuder-derivedconcentrations for phenanthrene and the less volatile PAH from the IOVPSaveraged 84±13% of the sorbent-derived values for the same experiment.That average is heavily dependent on the value for chrysene, but the gasphase concentrations of chrysene for the two sample types are well abovethe limits of quantitation and appear to be statistically different.Since the data of FIG. 9 indicate that phenanthrene was collected in thefirst two of three denuder sections with >90%-efficiency under thesampling conditions of this experiment, operation of the IOVPS withthree serially-connected sections is expected to lead to >99%efficiency. However, the apparent sorbent bed concentration may havebeen increased by “blow off’ artifacts from the filter-collectedparticulate phenanthrene and less volatile species fluoranthene throughchrysene.

EXAMPLE 1 Field Test for Nicotine in Environmental Tobacco Smoke

[0237] The IOVPS was used in the configuration shown in FIG. 2 todetermine nicotine in simulated environmental tobacco smoke. Thisconfiguration was intended to collect nicotine in the denuder sectionsand on the filter. Any nicotine blown-off the filter was trapped by thedownstream denuder section. The denuder sections had been coated withground XAD-4 resin as described above. Denuders were coated with XAD-4as described above. Denuders were extracted by sonication withspectroscopic-grade ethyl acetate with 0.01% triethylamine. Thetriethylamine prevents adsorption of nicotine to glass surfaces.Quinoline was added at the time of extraction as an internal standard tocorrect for any volatility losses during sample preparation. Theextracts were filtered with a Millipore Teflon filter of pore size 0.5micrometers, filter type FHUP, to separate the XAD-4 coating from theextracts. The extracts were concentrated to approximately 500microliters.

[0238] Extracts of denuders were analyzed for nicotine using anitrogen-phosphorous detector mounted on a Shimadzu GC-9A gaschromatograph with a DB-Wax 30 in×0.32 mm fused silica capillary column.5 The gas flow rates were: helium (primary carrier),1 mL/min; helium(make-up), 15 mL/min; hydrogen, 4 mL/min; and air, 75 mL/min. Thehydrogen and air flow rates were controlled through the Shimadzu GC-9A.The helium primary carrier and make-up gases were bypassed into aScientific Glass Engineering Unijector where their flow rates wereregulated. The injector was operated in splitless mode. Both theinjector port and the detector base were set to 250° C.

[0239] The column temperature program started at initial conditions of175“C. After 5 minutes, the temperature was increased linearly at a rateof 0.5° C./min for 10 minutes until the column temperature reached 180°C.

[0240] A Detector Engineering Technology (DET) nitrogen-phosphorousdetector with a ceramic .hermionic source was installed on the flameionization detector base of the Shimadzu GC-9A. Prior to sampleanalysis, the heating current of the DET Detector Current Supply, Model4000, was slowly increased until ignition of hydrogen-air chemistry wasachieved. Typical operating currents were approximately 3 amperes.

[0241] A Shimadzu Chromatopac C-R3A Data Processor was used to integratepeak areas during each sample run. Depending on the concentration of thesample, the sensitivity range and attenuation were manually adjusted onthe Chromatopac C-R3A to optimize chromatogram output. Under theseconditions, both nicotine and quinoline used as internal standard elutedbetween 5 and 6 minutes with excellent peak separation.

[0242] Two complete sampling trains were co-located and operatedsimultaneously. Three reference cigarettes were smoked sequentially in asealed environmental chamber (36 m³). About 45 minutes elapsed beforesampling began. Air was pulled through the IOVPS at 5 L/min for onehour. Nicotine was determined in denuder sections and filters using thedescribed method. The results are shown in Table 13, and they indicatethat the IOVPS can be used to trap nicotine from both the gas andparticle phases. Parallel sampling was conducted using Hammond et al.,method (Atmospheric Env., 21: 457-462, (1987). TABLE 13 Nicotine inEnvironmental Tobacco Smoke IOVPS microgram m⁻³ Hammond microgram m⁻³Denuder d1 (gas) 15.7 gas 23.6 Denuder d2 <0.24 Filter (particles) 0.64particles 0.89 Denuder d3 <0.24

[0243] The data can be used to calculate the phase distribution ofnicotine in ETS. Both gas and particulate nicotine levels measuredduring the same experiment with a single Hammond sampler were somewhathigher than obtained with the IOVPS.

EXAMPLE 2 Nicotine: Phase Distribution in ETS

[0244] This study was conducted in a 20 m³ stainless steel environmentalchamber with a surface area of 45.2 m². Six mixing fans (three inchestall) were staggered at ⅓ and ⅔ of the wall height with the axis of eachfan positioned at a 45° angle from the wall surface. All fans blew airin the same circular direction around the chamber. The mixing fans wereconnected in series to a variable voltage controller at a setting of 50volts and operated during, both the smoking and sampling periods. Thecirculation vents and chamber door were sealed with duct tape during theexperiment to minimize the air exchange rate. The chamber temperatureaveraged 24° C., and the relative humidity was approximately 22%. Afully automated smoking machine (Lawrence Berkeley Laboratory, Berkeley,Calif.) was connected to a puffer (Model ADL/II, Arthur D. Little,Cambridge, Mass.) and positioned on the floor in the center of the room.A brand of popular filtered commercial cigarettes were conditioned at60% relative humidity for more than 72 hours over an aqueous saturatedNaBr solution. The ignition of the first cigarette was designated aszero minutes. The cigarettes were sequentially burned for approximately11 minutes each starting at zero, 12, and 22 minutes. The cigarettessmoldered from an average length of 7.9 cm until they were extinguishedat an average butt length of 3.1 cm.

[0245] Five integrated organic vapor-particle samplers inserted andremoved in sequence collected nicotine for the first 189 minutes. Theventilation duct and chamber door was sealed shut with duct tape duringthe experiment to minimize the air exchange rate. At 189 minutes, thechamber door was opened.

[0246] Gas and particulate phase nicotine concentrations were measuredas a function of time using the IOVPS which consisted of two denudersfollowed by two 47 mm Teflon-coated glass fiber filters. The IOVPS wasinserted into the chamber through a port on the wall, and the samplerinlet extended approximately 60 cm into the room from the wall. Thedenuders were coated with ground XAD-4 (Alltech Associates, Inc.,Deerfield, IL) for the collection of gas phase nicotine, with the seconddenuder serving, as a backup. The first glass fiber filter collectedparticulate nicotine, and the second glass fiber filter was cleaned andcoated with an aqueous 4% NaHSO₄ solution (with 5% ETOH to wet thefilter) for collection of gas phase nicotine blown off (or “volatilized”or “evaporated”) from the particles on the upstream filter. Sampling at5 L/min via the house vacuum regulated through a mass flow controlleroccurred over five periods: 9-19 min, 20-30 min, 31-41 min, 89-109 min,and 169-189 min. Newly coated denuders and clean filters were used foreach sampling period. Unexposed XAD-4-coated denuders, Teflon-coatedclass fiber filters, and NaHSO₄-treated Teflon-coated glass fiberfilters were set aside for blank measurements.

[0247] The denuders were extracted by filling them with ethyl acetate(approximately 20 ml) containing 0.01% v/v TEA, adding 27 μg ofquinoline, and capping the ends. The denuders were then sonicated in awarm water bath (40° C.) for 15 minutes. The extracts were filteredthrough 47 mm Teflon filters (Type FHUP, Pore Size 0.5 μm, MilliporeCorporation, Bedford, MA) to remove any particles of the XAD-4 denudercoating, then a second extraction and filtration was performed. Thefiltrates were concentrated using a rotary evaporator (BrinkmannRotavapor-R) with a water bath set to 42° C. Final volumes ranged from183 to 428 μl. Extracts were transferred to vials for storage andanalysis. The 47 mm Teflon-coated glass fiber filters were extracted bycutting them into 0.5 cm² pieces and placing them into a 9 ml conicalvial, adding 3 ml of ethyl acetate with 0.01% v/v TEA, and spiking themwith 27 μg of quinoline. The glass fiber filters were sonicated for 15minutes and filtered using a Teflon filter. After a second extractionand filtration, the extracts were evaporated to final volumes rangingfrom 244 to 427 μl and transferred to vials for storage and analysis.

[0248] The 47 mm NaHSO₄-treated Teflon-coated class fiber filters wereextracted using the method outlined by Hammond et al in AtmosphericEnv., 21: 457-462. (1987). Filters were spiked with 27 μg of quinolinein ethyl acetate, and approximately one minute was allowed for the ethylacetate to evaporate at room temperature. The intact 47 mmNaHSO₄-treated glass fiber filters were inserted into test tubes. Toremove nicotine from the acid-coated filter, 100 μl ETOH was added towet the filter, followed by 2 ml water. After one minute of vortexing, 2ml of 10N NAOH was added to deprotonate nicotine in aqueous solution.The mixture was vortexed for one minute, then 500 ml ammoniated hexanewas added. In a fashion similar to TEA, ammonia suppresses adsorption ofnicotine onto glass. Another minute of vortexing is performed, therebytransferred nicotine to the organic hexane layer. The hexane wastransferred to a vial for storage and analysis. Final volumes of hexaneranged from 190 to 310 μl.

[0249] All samples were analyzed on the day of extraction using aShimadzu gas chromatograph obtained from Shimadzu Corporation, Kyoto,Japan. The helium primary carrier gas flow rate was set to 1 ml/minthrough a Scientific Glass Engineering, Unijector Control Module (SGEInc., Austin, TX). Samples were injected with a 5 μl SGE syringe intothe Shimadzu injector under splitless injection mode with septum purge.Injection volumes were 1.0±0.1 μl. The injector temperature was set to250° C. Compounds were separated on a DB-WAX fused silica capillarycolumn (30 m×0.32 mm, 0.25 μm film thickness, J&W, Folsom, Calif.). Theoven temperature was pro-rammed at 165° C. for 7 minutes and thenincreased at 17.5° C./min to a final temperature of 200° C. for 3minutes.

[0250] A DETector Engineering Technology (DET, Walnut Creek, Calif.)thermionic nitrogen-phosphorous detector (NPD) was mounted on top of theShimadzu flame ionization detector base. The additional gas flow ratessupplied to the detector were: helium make-up gas, 15 ml/min; hydrogen,4 ml/min; air, 75 ml/min. The detector heating block was set to 250° C.The NPD was powered by a DET current supply (Model 4000). Operatingcurrents used in these analyses ranged from 3.02 to 3.04 amperes.Signals were interpreted by the Shimadzu electrometer on the highestsensitivity range and plotted by the Shimadzu Chromatopac C-R3A dataprocessor. The C-R3A processor was programmed to integrate by peak area.Nicotine and quinoline eluted at approximately 5.4 min and 6.1 minrespectively, with excellent peak separation. New nicotine and quinolinestandards in ethyl acetate with 0.01% v/v TEA were prepared for theanalyses, and the same standards were used for the different extractionsfor consistency. All extractions and analyses were completed in ninedays. Nicotine and quinoline external standards were injectedperiodically between samples to obtain a drift correction for nicotineand quinoline response factors. Response factors decreased very slowlywith time due to the decrease in sensitivity of the NPD bead with time.A linear regression analysis of the response factors was performed foreach day of analysis and factored into nicotine and quinoline masscalculations for all injected samples.

[0251] All data were corrected for the percentage recovery of quinolineinternal standard. Quinoline is a convenient internal standard becauseit is chemically similar to nicotine, but it has been reported thatquinoline is present at about 1% of the nicotine concentration in ETS(Caka et al., Environ. Sci. Technol., 24:1196-1206. Since quinoline wasadded at levels similar to the amount of nicotine found in each sampler,errors due to quinoline in ETS were negligible in most cases. However,corrections for quinoline were applied when nicotine was underestimatedby more than 1%. Except where indicated, blank values were subtractedfrom the nicotine masses. Percent recoveries, blank masses for nicotine,limits of detection, and limits of quantitation are listed in Table 14.TABLE 14 Results of Quinoline Phase Distribution Study Sampler Recovery(%) Blank (μg) LOD (μg) LOD (μg) Sorbent Tubes 65-85 0.12 4 × 10⁻⁴ 1.3 ×10⁻³ Denuders  68-107 0.32 7 × 10⁻² 2.5 × 10⁻¹ 47 mm Uncoated 76-95b.d.* 4 × 10⁻⁴ 1.5 × 10⁻³ Filters 47 mm Bisulfate 44-71 0.08 5 × 10⁻⁴1.6 × 10⁻³ Filters High Vol. Filter 52-88 b.d.* 4 × 10⁻⁴ 1.3 × 10⁻³Sheets Stainless Steel 74-89 0.90 5 × 10⁻⁴ 1.6 × 10⁻³ Sheets

[0252] The gas-particle phase distribution was measured by the IOVPSsystem. The two denuders collected gas phase nicotine with the seconddenuder serving as a backup for breakthrough. The first glass fiberfilter collected particle phase nicotine, and blank values were belowdetection so no correction was made. The second glass fiber filter wascoated with 4% NaHSO₄ to collect volatilized nicotine from the particleson the first filter. Results are shown in Table 15. TABLE 15 Gas PhaseDistribution Time 1st 2nd 1st 2nd Period Interval Denuder Denuder FilterFilter 1  9-19 min 263 0 2.7 0 2 20-30 min 406   0.5 4.9 0 3 31-41 min449   6.3 5.0 0 4 89-109 min  131 0 1.6   0.2 5 169-189 min   74 0 4.0 0

[0253] Nicotine concentrations were taken from IOVPS gas phasemeasurements. Nicotine was collected in a glass sidestream smokeapparatus (225 cm³ volume), and an emission factor for the samecigarette brand was converted into an emission rate of 27.4 mg/h. Theventilation rate due to chamber leakage was determined before theexperiment by monitoring SF₆ tracer gas decay over 13 hours. The leakagerate was 0.152 m³/h. Ventilation due to sampling was 0.232 m³/h, and theloss rate due to deposition (v_(t)×surface area), which is analogous toventilation, was 0.576 m³/h. This yielded a total ventilation rate,Q_(T), of 0.96 m³/h.

1. A semi-volatile organic reversible gas sorbent for use in anintegrated diffusion vapor-particle sampler comprising, semi-volatilegas sorbent particles ranging in size between 0.05 and 10 microns. 2.The sorbent of claim 1 , wherein the particles range in size frombetween 0.1 and 7 μm.
 3. The sorbent of claim 2 , wherein the particlesrange in size from between 0.2 and 4 μm.
 4. The sorbent of claim 3 ,wherein the particles range in size from between 0.3 and 3.0 μm.
 5. Thesorbent of claim 4 , wherein the particles range in size from between0.5 and 1.5 μm.
 6. The sorbent of claim 1 , wherein the surface tovolume ratio of the particles is 200,000 to 4,000 cm⁻¹.
 7. The sorbentof claim 6 , wherein the surface to volume ratio of the particles is100,000 to 50,000 cm⁻¹.
 8. The sorbent of claim 7 , wherein the surfaceto volume ratio of the particle is about 80,000 cm⁻¹.
 9. A method ofmaking the sorbent of claim 1 , comprising grinding a reversiblesemi-volatile organic reversible gas sorbent starting material intoparticles ranging in size between 0.05 and 10 μm.
 10. The method ofclaim 9 , wherein the starting material used for grinding is amacroreticular polymeric resin.
 11. The method of claim 10 , wherein theresin is a styrene-divinylbenzene copolymer.
 12. The method of claim 11, wherein the resin is selected from XAD-1, XAD-2, XAD-4, XDA-16, OstionSP-l, Chromosorb 101, Chromosorb 102, Porapak P, and Envi-chrom P. 13.The method of claim 10 wherein the resin is a polyaromatic orpolystyrene polymer or copolymer.
 14. The method of claim 13 , whereinthe resin is selected from Chromosorb 103, Chromosorb 105, andChromosorb
 106. 15. The method of claim 10 , wherein the resin isethylvinylbenzene or polyalkyl styrene.
 16. The method of claim 15 ,wherein the resin is selected from Synachrome, Porapak Q, Super Q, andGaschrom
 254. 17. The method of claim 9 , wherein the resin is amethylmethacrylate, methacrylate-divinylbenzene, ormethacrylate-styrene.
 18. The method of claim 17 , wherein the resin isXAD-7, XAD-8, Spheron MD, Spheron SE, Chromosorb 107, Chromosorb 108,Amberchrom CG-71, Amberchrom CG-161.
 19. The method of claim 9 , whereinthe starting material is a porous polymeric resin.
 20. The method ofclaim 19 , wherein the resin is diphenyl-p-phenylene oxide resin. 21.The method of claim 20 , wherein said resin is Tena-TA.
 22. The methodof claim 9 , wherein the material is a carbonaceous material.
 23. Themethod of claim 22 , wherein the material is selected from graphite,carbon blacks, and activated carbons.
 24. The method of claim 9 ,wherein the material is an activated carbon, polymeric resincombination.
 25. The method of claim 24 , wherein the material isselected from Ambersorb 340, Ambersorb 348, Ambersorb 563, Ambersorb564, Ambersorb 575, and a polyphenylene matrix filled with graphitizedcarbon (Tenax GR).
 26. The method of claim 9 , wherein the startingmaterial has a surface area of 35-2400 m²/g.
 27. The method of claim 26, wherein the surface area is between 400 and 1600 m²/g.
 28. The methodof claim 27 , wherein the surface area is about 800 m²/g.
 29. The methodof claim 1 , wherein the starting material has a pore size of between30-2000 Å.
 30. The method of claim 29 , wherein the starting materialhas a pore size of between 40-200 Å.
 31. The method of claim 30 ,wherein the starting material has a pore size of about 50 Å.
 32. Themethod of claim 9 , wherein the starting material is electricallyneutral and polarizable.
 33. A method of making an improved integrateddiffusion vapor-particle sampler comprising; a) etching the innersurface of a diffusion chamber, b) suspending the semi-volatile organicgas sorbent particles of claim 1 in an organic solvent, c) contactingthe etched surface with the suspension, d) depositing the sorbent onsaid surface, e) optionally, washing said surface with the organicsolvent, and f) positioning a particle filter down stream of thediffusion chamber.
 34. The method of claim 33 , wherein said etching isby sand blasting, acid etching, or rubbing with an abrasive powder. 35.The method of claim 33 , wherein said suspension is by sonicating orvortex mixing.
 36. The method of claim 33 , wherein the suspension is inthe proportion of 100-300 mg particles/30 ml organic solvent.
 37. Themethod of claim 36 , wherein the suspension is in the proportion of50-500 mg particles/30 ml organic solvent.
 38. The method of claim 37 ,wherein the suspension is in the proportion of 200 mg particles/30 mlorganic solvent.